WEST LAFAYETTE, Ind. – Purdue
University scientists are part of a nationwide effort to save a declining
species of an amphibian called the hellbender, with hopes of rallying people to
do the same.

The group is trying to save
North America's largest salamander, also known as a "devil dog" and
"old lasagna sides." These giant salamanders are typically 11-24
inches long with flat green or brown bodies that have noticeable wrinkles on
the sides. They are long-lived and spend up to 30 years under flat rocks in
rivers and streams across Appalachia, parts of the Midwest and the northern
tips of several southern states.

But the eastern hellbender
is endangered in five states and protected or of special concern in many
others.

"Their populations are declining
in many of their geographic locations," said Rod Williams, a Purdue
assistant professor of forestry and natural resources and leader of the
university's hellbender efforts. "This species has hardly changed in 160
million years of existence, so we think it's worth the effort to do our part to
save this living fossil."

Surveys in Indiana starting
in 1998 showed that populations had not only declined, but that the remaining hellbenders
were in particular danger. Investigators have found eggs and older adults, but
not much in between.

"We're not finding many
of them, and the ones we're finding are all adults, which indicates that their
population is not doing well," said Katie Smith, wildlife diversity
program manager for the Indiana Department of Natural Resources, who has led
state efforts to look for Hellbenders.

As part of the effort to
increase Indiana hellbender populations, Purdue scientists are relocating the
amphibians to areas that have seen decline. The group obtained 18 juvenile hellbenders
that were originally collected in West Virginia. The hellbenders spent time in a
zoo in Texas and then were reared at Purdue until they reached 4 years old – the
point at which they are no longer easy prey for predators. Eight were released
in Southern Indiana last month. The others will find new homes in the coming
months.

Before the release, a radio
transmitter was inserted into each hellbender to allow the scientists to track their
movements. That information will help build understanding about habitats that
are suitable for hellbenders and their movement in rivers, and track their
survival.

The eastern hellbender is
currently found across Applachia and parts of the Midwest, as well as small
portions of a few southern states. (Map created by Bart Kraus, Purdue graduate
student)Download Photo

"What I hope is that in
five years, 10 years - as the Indiana DNR continues to do surveys - that
they'll start to see the numbers rebound and they'll see some of those other
age classes and natural reproduction that doesn't require us to
intervene," said Steve Kimble, a Purdue post-doctoral researcher working
with Williams.

The next step is to survey other
locations throughout the state to evaluate their suitability for future hellbender
reintroductions.

In the laboratory, Williams
and Zach Olson, a former post-doctoral researcher at Purdue and current
assistant research professor at the University of New England, showed that they
could detect a hellbender's DNA from samples of moving water (termed eDNA
sampling) in areas the species is thought to live. Their findings were
published in the current issue of the journal Wildlife Research.

The method is especially
valuable because traditional detection methods required people to literally
turn over stones in rivers and visually spot a hellbender. It is time-consuming
and dangerous for the surveyors and the hellbenders, which could be injured or
killed if a rock slipped or pinched them during lifting.

The eDNA method also speeds
research aimed at saving the species.

"We don't have to cover
hundreds of meters of water in a day now," Olson said. "We can cover
an entire watershed in a day."

Beyond the scientists'
efforts, saving hellbenders will take buy-in from people who live in the areas
surrounding the rivers and streams where the animals live. Recreational users
need to know that if they encounter a hellbender or snag one with a fishing
line that the animal needs to be released as quickly and gently as possible –
preferably by cutting the line.

Outreach specialists and
social scientists are developing publications and programs that will increase
awareness about hellbenders and provide tips on how to reverse population
decline. The effort includes lesson plans for teachers and information about
how homeowners and land managers can help keep local water clean. The group has
launched a website - http://www.helpthehellbender.org - to serve as a clearinghouse
for information.

"We have to make sure
people know what to do if they catch one and make sure that people know they
need to keep water clean," said Linda Prokopy, a Purdue associate
professor of natural resources planning. "The awareness right now is
pretty low, especially among the general population."

Nathan Mullendore, a
research associate and outreach coordinator for the project, said fewer than
half the people surveyed around hellbender habitats had ever heard of the
amphibian, and only half of the those polled had claimed to have ever seen one.
Once informed, however, those same people showed interest in helping hellbender
populations.

"When you have
something that's so special and so unique, I think it gives people an extra
reason to care about local environmental quality," Mullendore said.
"This is not just about one animal. It's about the ecosystem that supports
all of us."

An eDNA Approach to
Detect Eastern Hellbenders (Cryptobranchus a. alleganiensis) Using Samples of Water

Zachary H. Olson, Jeffrey T. Briggler and Rod N.
Williams

Context: Environmental DNA, or eDNA, methods are a novel application of
non-invasive genetic sampling in which DNA from organisms is detected via sampling of water or
soil, typically for the purposes of determining the presence or
absence of an organism. eDNA methods have the potential to revolutionise the
study of rare or endangered taxa.

Aims: We evaluated the efficacy of eDNA
sampling to detect populations of an amphibian of conservation concern, the
eastern hellbender (Cryptobranchus a. alleganiensis), indirectly from their
aquatic environments.

Methods: We developed species-specific
primers, validated their specificity and sensitivity, and
assessed the utility of our methods in silico and in laboratory trials. In the field,
we collected water samples from three sites with known densities of
hellbenders, and from one site where hellbenders do not occur. We filtered
water samples, extracted DNA from filters, and assayed the
extraction products for hellbender DNA by using polymerase chain reaction (PCR)
and gel electrophoresis.

Key results: Our methods detected hellbenders at
densities approaching the lowest of reported natural densities. The low-
density site (0.16 hellbenders per 100 m2) yielded two positive amplifications,
the medium-density site (0.38 hellbenders per 100 m2) yielded eight positive amplifications,
and the high-density site (0.88 hellbenders per 100 m2) yielded 10 positive amplifications.
The apparent relationship between density and detection was obfuscated when
river discharge was considered. There was no amplifications in any negative
control.

Conclusion: eDNA methods may represent a
cost-effective means by which to establish broad-scale patterns of occupancy
for hellbenders.

Implications: eDNA can be considered a valuable
tool for detecting many species that are otherwise difficult
to study.